Plasma processing method and plasma processing apparatus

Abstract

A plasma processing method includes: (a) a step of providing a substrate on a substrate support portion in a chamber, the substrate having a base film, a first film on the base film, and a second film on the first film, the first film and the second film providing an opening exposing the base film, the second film including silicon; and (b) a step of removing the second film using plasma generated from a processing gas, the plasma including hydrogen fluoride etchant, without supplying an electric bias to the substrate support portion or supplying an electric bias having a level of 200 W or less or 1 kV or less to the substrate support portion.

Description

Technical Field

[0001] The exemplary embodiments of this disclosure relate to plasma processing methods and plasma processing apparatus. Background Technology

[0002] Patent Document 1 discloses a plasma etching method comprising a first step, a second step, and a third step. In the first step, a photoresist film having a pattern formed on a mask film is subjected to plasma treatment. In the second step, the mask film is etched using plasma along the pattern of the plasma-treated photoresist film, exposing an organic film formed beneath the mask film. In the third step, the organic film is etched using plasma containing a mixed gas of O2, COS, and Cl2.

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2015-12178 Summary of the Invention

[0004] The problem that the invention aims to solve This disclosure provides a technique for selectively removing silicon-containing films relative to other films.

[0005] Methods for solving problems In one exemplary embodiment, the plasma processing method includes: (a) a step of providing a substrate to a substrate support in a chamber, the substrate having a base film, a first film on the base film, and a second film on the first film, the first film and the second film having openings that expose the base film, the second film comprising silicon; and (b) a step of removing the second film using plasma generated by a processing gas, wherein the plasma comprises a hydrogen fluoride etchant, by not supplying an electrical bias to the substrate support, or by supplying an electrical bias having a level of 200W or less or 1kV or less to the substrate support.

[0006] Invention Effects According to one exemplary embodiment, a technique is provided that allows for the selective removal of silicon-containing films relative to other films. Attached Figure Description

[0007] Figure 1 This is a diagram illustrating an example of the configuration of a plasma processing system.

[0008] Figure 2 This is a diagram illustrating an example of the configuration of an inductively coupled plasma processing device.

[0009] Figure 3 This is a flowchart illustrating a plasma processing method according to an exemplary embodiment.

[0010] Figure 4 It is applicable Figure 3 A partial magnified view of a substrate as an example of the method.

[0011] Figure 5 This is a cross-sectional view showing one step of a plasma processing method according to an exemplary embodiment.

[0012] Figure 6 This is a cross-sectional view showing one step of a plasma processing method according to an exemplary embodiment.

[0013] Figure 7 This is a cross-sectional view showing one step of a plasma processing method according to an exemplary embodiment.

[0014] Figure 8 This is a cross-sectional view showing one step of a plasma processing method according to an exemplary embodiment. Detailed Implementation

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are referred to by the same reference numerals, and repeated descriptions are omitted.

[0016] Figure 1 This is a diagram illustrating an example of the configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. Furthermore, the plasma processing chamber 10 has at least one gas supply port for supplying at least one type of processing gas to the plasma processing space and at least one gas outlet for discharging gas from the plasma processing space. The gas supply port is connected to the gas supply unit 20 (described later), and the gas outlet is connected to the exhaust system 40 (described later). The substrate support 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0017] The plasma generation unit 12 is configured to generate plasma from at least one type of processing gas supplied to the plasma processing space. The plasma formed in the plasma processing space can also be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR), helicon wave plasma (HWP), or surface wave plasma (SWP), etc. Furthermore, various types of plasma generation units, including AC (Alternating Current) plasma generation units and DC (Direct Current) plasma generation units, can be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes RF (Radio Frequency) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0018] The control unit 2 processes computer-executable commands that cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 2 can be configured to control the various elements of the plasma processing apparatus 1 in a manner that executes the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may also include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 can be configured to perform various control actions by reading a program from the storage unit 2a2 and executing the read program. The program may also be pre-stored in the storage unit 2a2, or retrieved via a medium if necessary. The retrieved program is stored in the storage unit 2a2, and is read from and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a, or a communication line connected to the communication interface 2a3. The processing unit 2a1 may also be a CPU (Central Processing Unit). The storage unit 2a2 may also include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may also communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

[0019] Hereinafter, an example of the configuration of an inductively coupled plasma processing apparatus 1 will be described. Figure 2 This is a diagram illustrating an example of the configuration of an inductively coupled plasma processing device.

[0020] The inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing chamber 10 includes a dielectric window 101. Furthermore, the plasma processing apparatus 1 includes a substrate support 11, a gas inlet unit, and an antenna 14. The substrate support 11 is disposed within the plasma processing chamber 10. The antenna 14 is disposed on or above the plasma processing chamber 10 (i.e., on or above the dielectric window 101). The plasma processing chamber 10 has a plasma processing space 10s defined by the dielectric window 101, the sidewalls 102 of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded.

[0021] The substrate support portion 11 includes a body portion 111 and an annular assembly 112. The body portion 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the annular assembly 112. A wafer is an example of a substrate W. In a top view, the annular region 111b of the body portion 111 surrounds the central region 111a of the body portion 111. The substrate W is disposed on the central region 111a of the body portion 111, and the annular assembly 112 is disposed on the annular region 111b of the body portion 111 in such a way that it surrounds the substrate W on the central region 111a of the body portion 111. Therefore, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as an annular support surface for supporting the annular assembly 112.

[0022] In one embodiment, the body portion 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a bias electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. It should be noted that other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may also have an annular region 111b. In this case, the annular assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode, combined with the RF power supply 31 and / or DC power supply 32 described later, can also be disposed within the ceramic component 1111a. In this case, the at least one RF / DC electrode functions as a bias electrode. It should be noted that the conductive component of the base 1110 and the at least one RF / DC electrode can also function as multiple bias electrodes. In addition, the electrostatic electrode 1111b can also function as a bias electrode. Therefore, the substrate support portion 11 includes at least one bias electrode.

[0023] The annular assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more boundary rings and at least one cover. The boundary rings are formed of a conductive or insulating material, and the cover is formed of an insulating material.

[0024] Furthermore, the substrate support 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck 1111, the annular assembly 112, and the substrate to a target temperature. The temperature control module may also include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. In the flow path 1110a, a heat transfer fluid such as brine or gas flows. In one embodiment, the flow path 1110a is formed within the base 1110, and one or more heaters are disposed within the ceramic component 1111a of the electrostatic chuck 1111. Additionally, the substrate support 11 may also include a heat transfer gas supply section configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0025] The gas inlet section is configured to introduce at least one type of processing gas from the gas supply section 20 into the plasma processing space 10s. In one embodiment, the gas inlet section includes a central gas injector (CGI) 13. The central gas injector 13 is disposed above the substrate support section 11 and is mounted at a central opening formed in the dielectric window 101. The central gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas inlet port 13c. The processing gas supplied to the gas supply port 13a passes through the gas flow path 13b and is introduced into the plasma processing space 10s through the gas inlet port 13c. It should be noted that the gas inlet section may also include, in addition to or in place of the central gas injector 13, one or more side gas injectors (SGIs) mounted at one or more openings formed in the sidewall 102.

[0026] The gas supply unit 20 may also include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one type of process gas from its respective gas source 21 to its respective flow controller 22 to the gas inlet unit. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include at least one flow modulation device for modulating or pulsed the flow rate of the at least one type of process gas.

[0027] The power supply 30 includes an RF power supply 31 connected to the plasma processing chamber 10 via at least one impedance integration circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one bias electrode and antenna 14. Plasma is thus formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to at least one bias electrode, a bias potential can be generated in the substrate W, and ions from the formed plasma can be introduced into the substrate W.

[0028] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is connected to the antenna 14 via at least one impedance integration circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10MHz to 150MHz. In one embodiment, the first RF generation unit 31a may also be configured to generate multiple source RF signals with different frequencies. The generated one or more source RF signals are supplied to the antenna 14.

[0029] The second RF generation unit 31b is configured by combining at least one impedance integration circuit with at least one bias electrode to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than that of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generation unit 31b may also be configured to generate multiple bias RF signals with different frequencies. The generated one or more bias RF signals are supplied to at least one bias electrode. Furthermore, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0030] Furthermore, the power supply 30 may also include a DC power supply 32 integrated with the plasma processing chamber 10. The DC power supply 32 includes a bias DC generation unit 32a. In one embodiment, the bias DC generation unit 32a is connected to at least one bias electrode and configured to generate a bias DC signal. The generated bias DC signal is applied to at least one bias electrode.

[0031] In various embodiments, the bias DC signal can also be pulsed. In this case, a sequence of voltage pulses is applied to at least one bias electrode. The voltage pulses can also have rectangular, trapezoidal, triangular, or combinations thereof pulse waveforms. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from the DC signal is connected between the bias DC generation unit 32a and at least one bias electrode. Therefore, the bias DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. The voltage pulses can have positive or negative polarity. Furthermore, the sequence of voltage pulses can also include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. It should be noted that the bias DC generation unit 32a can be provided in addition to the RF power supply 31, or it can replace the second RF generation unit 31b.

[0032] Antenna 14 includes one or more coils. In one embodiment, antenna 14 may also include an outer coil and an inner coil arranged coaxially. In this case, RF power supply 31 may be connected to both the outer coil and the inner coil, or to either the outer coil or the inner coil. In the former case, the same RF generating unit may be connected to both the outer coil and the inner coil, or a separate RF generating unit may be connected to each of the outer coil and the inner coil.

[0033] The exhaust system 40 may be connected, for example, to a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may also include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s is adjusted using the pressure regulating valve. The vacuum pump may also include a turbomolecular pump, a dry vacuum pump, or a combination thereof.

[0034] Figure 3 This is a flowchart illustrating a plasma processing method according to an exemplary embodiment. Figure 3 The plasma processing method MT1 shown (hereinafter referred to as "method MT1") can be executed by the plasma processing apparatus 1 of the above embodiment. Method MT1 can be applied to Figure 4 The substrate W.

[0035] Figure 4 It is applicable Figure 3 A cross-sectional view of a substrate, as an example of the method. For example... Figure 4 As shown, in one embodiment, the substrate W has a base film UF, a first film F1 on the base film UF, and a second film F2 on the first film F1. The base film UF, the first film F1, and the second film F2 may also contain different materials from each other.

[0036] The first film F1 can also be a carbon-containing film or a metal-containing film. The carbon-containing film can also include at least one of the following: spin-coated carbon and amorphous carbon. The metal-containing film can also include at least one of the following: alumina (Al2O3), titanium nitride (TiN), tungsten carbide (WC), and zirconium oxide (ZrO2). The first film F1 can also be silicon-free.

[0037] The second film F2 contains silicon. That is, the second film F2 is a silicon-containing film. The silicon-containing film may also contain at least one of the following: silicon oxynitride (SiON), SOG (Spin On Glass), silicon oxide (SiO2), silicon carbide (SiC), and silicon nitride (SiN).

[0038] The substrate UF can be a metal-containing film or a silicon-containing film. Examples of metal-containing and silicon-containing films can be the same as those in film 1 F1 or film 2 F2. The substrate UF can also be a silicon-containing film of a different type than film 2 F2. The substrate UF can also be a metal-containing film of a different type than film 1 F1.

[0039] The substrate W may further have a mask MK on the second film F2. The mask MK may also contain a photoresist. The mask MK may also have at least one aperture OPM. The spacing of the aperture OPM may also be less than 80 nm. The spacing of the aperture OPM can be measured at the top of the aperture OPM (the top of the mask MK).

[0040] Hereinafter, for method MT1, we will take the case where method MT1 is applied to substrate W using the plasma processing apparatus 1 of the above embodiment as an example, referring to... Figures 3-8 Please provide an explanation. Figures 5-8 This is a cross-sectional view showing one step of a plasma processing method according to an exemplary embodiment. When using a plasma processing apparatus 1, method MT1 can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 using the control unit 2. In method MT1, as... Figure 2 As shown, the substrate W disposed on the substrate support 11 within the plasma processing chamber 10 is processed.

[0041] like Figure 3 As shown, method MT1 may also include steps ST1 to ST6. Steps ST1 to ST6 may be performed sequentially. Step ST4 may be performed before or simultaneously with step ST5. Method MT1 may also exclude at least one of steps ST2 to ST4 and step ST6.

[0042] (Process ST1) In process ST1, Figure 4The substrate W shown is provided on the substrate support 11 within the plasma processing chamber 10.

[0043] (Process ST2) In process ST2, such as Figure 5 As shown, the second film F2 is etched through the opening OPM of the mask MK using plasma PL generated by the process gas, forming the first opening OP1 in the second film F2. The first opening OP1 corresponds to the opening OPM. The first opening OP1 exposes the first film F1.

[0044] Process ST2 can also be performed as follows: Processing gas is supplied to the plasma processing chamber 10 using the gas supply unit 20. The control unit 2 controls the gas supply unit 20 and the plasma generation unit 12 in a manner that plasma PL is generated from the processing gas.

[0045] (Process ST3) In process ST3, such as Figure 6 As shown, the first film F1 is etched using the first plasma PL1 generated by the first processing gas, forming a second opening OP2 in the first film F1. The second opening OP2 corresponds to the first opening OP1. The opening OP, including the first opening OP1 and the second opening OP2, exposes the substrate film UF. That is, the first film F1 and the second film F2 provide openings OP that expose the substrate film UF. The spacing of the openings OP can also be 80 nm or less. The spacing of the openings OP can be measured at the upper end of the opening OP (above the second film F2). In the case where method MT1 does not include steps ST2 to ST4, in step ST1, it is also possible to... Figure 6 The substrate W shown is provided onto the substrate support 11. In the case where method MT1 does not include steps ST2 and ST4, in step ST1, it is also possible to... Figure 5 The substrate W shown is provided on the substrate support portion 11.

[0046] Step ST3 can also be performed as follows: The first processing gas is supplied to the plasma processing chamber 10 using the gas supply unit 20. The control unit 2 controls the gas supply unit 20 and the plasma generation unit 12 in a manner that generates the first plasma PL1 from the first processing gas.

[0047] (Process ST4) In process ST4, such as Figure 7As shown, a deposit DP is formed on the base film UF exposed within the opening OP. The deposit DP can also be formed using a plasma PLD. The plasma PLD can also be generated by a processing gas containing hydrogen halide gas and a carbon-containing gas without supplying an electrical bias to the substrate support 11. The hydrogen halide gas can also be hydrogen fluoride (HF), hydrogen chloride (HCl), or hydrogen bromide (HBr). The carbon-containing gas can also be a hydrocarbon (C). x H y ) gas, fluorocarbon (C x F y ) gas or hydrofluorocarbon (C x H y F z Gas. x, y, and z are each positive real numbers. Deposits (DP) can also contain carbon. Deposits (DP) can also be formed by the movement of fluid carbonaceous material on the sidewalls of the opening (OP) and its accumulation on the basement membrane (UF).

[0048] Process ST4 can also be performed as follows: Processing gas is supplied to the plasma processing chamber 10 using the gas supply unit 20. The control unit 2 controls the gas supply unit 20 and the plasma generation unit 12 in a manner that generates plasma PLD from the processing gas.

[0049] (Process ST5) In process ST5, such as Figure 8 As shown, the second film F2 is removed using a second plasma PL2 generated from the second process gas. The second plasma PL2 contains a hydrogen fluoride etchant (HF etchant). At the end of step ST5, a residual deposit DP may also remain on the substrate film UF. The hydrogen fluoride etchant etches the second film F2, which is a silicon-containing film. The hydrogen fluoride etchant may also contain hydrogen fluoride active species and neutral molecules of hydrogen fluoride. The hydrogen fluoride active species may also contain hydrogen fluoride ions and hydrogen fluoride radicals. In the second plasma PL2, hydrogen fluoride etchant with HF bonds is generated because HF bonds are difficult to dissociate.

[0050] In process ST5, the second processing gas may also contain hydrogen and fluorine. The second processing gas may also contain at least one selected from the group consisting of a mixture of hydrogen-containing and fluorine-containing gases, hydrogen fluoride gas, and hydrofluorocarbon gas. The hydrogen-containing gas may, for example, be H2, NH3, H2O, H2O2, or hydrogen-carbon (CH4, C3H6, etc.). The fluorine-containing gas may also be NF3, SF6, WF6, XeF2, fluorocarbon, or hydrofluorocarbon. In one example, the mixture of hydrogen and fluorine may also contain H2 and CF4. The hydrofluorocarbon gas may also be selected from CHF3, CH2F2, CH3F, C2HF5, C2H2F4, C2H3F3, C2H4F2, C3HF7, C3H2F2, C3H2F6, C3H2F4, C3H3F5, C4H5F5, C4H2F6, C5H2F6, C5H2F7 ... 10 At least one of the groups consisting of c-C5H3F7 and C3H2F4.

[0051] In process ST5, the second processing gas may further include a selection of inert gases and fluorocarbon gases (C). x F y The gas is selected from at least one of the following groups: gases and phosphorus-containing gases. Inert gases may also be noble gases or nitrogen (N2). Examples of noble gases include argon. Fluorocarbon gases may also be selected from at least one of the following groups: CF4, C2F2, C2F4, C3F8, C4F6, C4F8, and C5F8. Phosphorus-containing gases may also include at least one of the following groups: phosphorus trifluoride (PF3), phosphorus pentafluoride (PF5), phosphorus trichloride (PCl3), phosphorus pentachloride (PCl5), phosphorus tribromide (PBr3), phosphorus pentabromide (PBr5), and phosphorus iodide (PI3).

[0052] In process ST5, the second processing gas may not contain any carbon-containing gases. Of all the gases contained in the second processing gas, excluding precious gases, hydrogen fluoride gas may have the highest flow rate. The ratio of the combined flow rate of fluorocarbon and hydrofluorocarbon gases to the total flow rate of the second processing gas may be 0.1 or less. The ratio of the flow rate of phosphorus-containing gases to the total flow rate of the second processing gas may also be 0.1 or less.

[0053] In step ST5, the electrical bias may not be supplied to the substrate support 11, or in step ST3, the electrical bias may be supplied to the substrate support 11 at a level lower than that supplied to the substrate support 11. In step ST5, the electrical bias may not be supplied to the substrate support 11, or the electrical bias at a level of 200W or less or 1kV or less may be supplied to the substrate support 11.

[0054] Electrical bias can also refer to biasing RF power. In this case, the level of electrical bias is the power level (RMS) of the biasing RF power. The level of electrical bias can be below 200W, below 100W, or below 50W.

[0055] Electrical bias can also be a direct current (DC) voltage. A DC voltage can also include a voltage pulse. In this case, the level of electrical bias is the absolute value of the voltage level of the voltage pulse. The level of electrical bias can be below 1kV, below 500V, or below 100V.

[0056] In process ST5, an electrical bias may also be supplied to the substrate support 11. In this case, the ionization energy generated by the second plasma PL2 and injected into the substrate W may be less than 500 eV. The ionization energy disclosed herein may also be the average ionization energy injected onto the substrate. The average ionization energy may be calculated, for example, from the process conditions and the magnitude of the electrical bias supplied to the substrate support 11 (the power level of the bias RF power, the voltage level of the voltage pulse), or it may be calculated based on simulation results.

[0057] In process ST5, the temperature of the substrate support 11 can be below 60°C or below 30°C. In process ST5, the pressure inside the plasma processing chamber 10 can be above 6.67 Pa (50 mTorr) or above 13.3 Pa (100 mTorr).

[0058] Process ST5 may also include a first period and a second period alternating with the first period. The first and second periods are configured alternately. During the first period, a first source RF signal for generating the second plasma PL2 is supplied. The first source RF signal has a first level. During the second period, no source RF signal is supplied, or a second source RF signal with a second level lower than the first level is supplied.

[0059] Step ST5 can also be performed as follows: The second processing gas is supplied to the plasma processing chamber 10 using the gas supply unit 20. The control unit 2 controls the gas supply unit 20 and the plasma generation unit 12 in a manner that generates the second plasma PL2 from the second processing gas.

[0060] After step ST5, the substrate film UF can also be etched using plasma generated by the processing gas. In this case, an opening corresponding to the second opening OP2 of the first film F1 is formed in the substrate film UF. If deposit DP remains on the substrate film UF at the end of step ST5, the substrate film UF can be etched using plasma generated by the processing gas after the deposit DP is removed.

[0061] (Process ST6) In step ST6, the first membrane F1 is removed within the plasma processing chamber 10. The first membrane F1 can also be removed using plasma generated from a processing gas containing oxygen-containing gas. The oxygen-containing gas can also be oxygen (O2). Step ST6 can be performed in the same plasma processing chamber 10 as step ST5, or it can be performed continuously with step ST5.

[0062] If the above method MT1 is used, then in step ST5, the silicon-containing film (second film F2) can be selectively removed relative to the other films (first film F1). The hydrogen fluoride etchant contained in the second plasma PL2 reacts more readily with the silicon-containing film than with the other films. As a result, the etching rate of the first film F1 becomes lower than the etching rate of the second film F2.

[0063] Furthermore, by using the method MT1 described above, the etching of the first film F1 can be suppressed, thereby suppressing the etching of the sidewall of the second opening OP2 that defines the first film F1. Therefore, the generation of shape anomalies (bow-shaped) on the sidewall defining the second opening OP2 can be suppressed.

[0064] When the substrate UF is a metal-containing film, the hydrogen fluoride etchant contained in the second plasma PL2 in process ST5 is insufficient to etch the substrate UF. Therefore, it is difficult to generate metal residue from the substrate UF.

[0065] In the case where method MT1 includes step ST4, the substrate film UF is protected by the deposited DP in step ST5. Therefore, even when the substrate film UF is a silicon-containing film, the etch selectivity of the second film F2 relative to the substrate film UF can be improved.

[0066] If the pressure in the plasma processing chamber 10 in process ST5 is 6.67 Pa or higher, then the etching selectivity of the second film F2 relative to the first film F1 can be improved in process ST5.

[0067] The following describes various experiments conducted to evaluate method MT1. The experiments described below are not intended to limit this disclosure.

[0068] (Experiment 1) In the first experiment, a substrate was first provided to a substrate support within the chamber of the plasma processing apparatus. The substrate has a... Figure 6 The substrate W shown has a similar structure. The substrate has a silicon oxide film, an amorphous carbon film on the silicon oxide film, and a SiON film on the amorphous carbon film. The amorphous carbon film and the SiON film provide openings that expose the silicon oxide film.

[0069] Next, without supplying electrical bias to the substrate support, plasma is generated using a processing gas containing hydrogen fluoride and argon. This plasma is then used to remove the SiON film. The temperature of the substrate support is 0°C. The pressure within the chamber is 66.7 Pa. The power level of the RF source used to generate the plasma is 1000 W.

[0070] (Experiment 2) Except for setting the temperature of the substrate support to 30°C, the experiment was conducted in the same manner as the first experiment.

[0071] (Experiment 3) Except for setting the temperature of the substrate support to 60°C, the experiment was conducted in the same manner as the first experiment.

[0072] (Results of Experiment 1) In each of Experiments 1 through 3, the cross-section of the substrate was observed. In Experiments 1 through 3, the SiON film was removed. In Experiments 1 through 3, no shape anomalies (arches) were observed on the sidewalls of the openings marking the amorphous carbon film.

[0073] (Experiment 4) In the fourth experiment, the substrate was provided to the substrate support in the same manner as in the first experiment.

[0074] Next, without supplying electrical bias to the substrate support, plasma is generated using a processing gas containing hydrogen fluoride, CH3F, and argon. This plasma is then used to remove the SiON film. The temperature of the substrate support is 0°C. The pressure within the chamber is 1.33 Pa. The power level of the RF source used to generate the plasma is 2000 W.

[0075] (Experiment 5) Except that the pressure inside the chamber was set to 13.3 Pa, the experiment was conducted in the same manner as the fourth experiment.

[0076] (Experiment 6) Using a processing gas containing nitrogen instead of argon, the temperature of the substrate support was set to 60°C and the pressure inside the chamber was set to 13.3 Pa. Otherwise, the experiment was conducted in the same manner as in Experiment 4.

[0077] (Experiment 7) The experiment was conducted in the same manner as in Experiment 4, except that a treatment gas containing C4F6 gas was used instead of CH3F gas.

[0078] (Experiment 8) Except that the pressure inside the chamber was set to 13.3 Pa, the experiment was conducted in the same manner as in Experiment 7.

[0079] (Experiment 9) The temperature of the substrate support was set to 60°C, and the power level of the source RF power was set to 250W. Otherwise, the experiment was conducted in the same manner as in Experiment 7.

[0080] (Experiment 10) The temperature of the substrate support was set to 60°C, the power level of the source RF power was set to 250W, and the pressure inside the chamber was set to 13.3Pa. Otherwise, the experiment was conducted in the same manner as in Experiment 7.

[0081] (Experiment 11) Using a treatment gas containing nitrogen instead of argon, the pressure in the chamber was set to 13.3 Pa. Otherwise, the experiment was conducted in the same manner as in Experiment 7.

[0082] (Results of Experiment 2) In each of experiments 4 through 11, cross-sections of the substrate were observed. In experiments 4 through 11, deposits were formed on the silicon oxide film exposed within the openings of the amorphous carbon film (see reference). Figure 7 ).

[0083] The above descriptions illustrate various illustrative embodiments, but the implementation is not limited to these illustrative embodiments. Various additions, omissions, substitutions, and modifications can be made. Furthermore, elements from different embodiments can be combined to form other embodiments.

[0084] Hereinafter, various exemplary embodiments contained in this disclosure are described in [E1] to [E19].

[0085] [E1] A plasma processing method comprising: (a) A process of providing a substrate to a substrate support in a cavity, the substrate having a base film, a first film on the base film, and a second film on the first film, the first film and the second film having openings exposing the base film, the second film comprising silicon; and (b) A process in which the second film is removed by using plasma generated by a processing gas, wherein the second film is removed by not supplying an electrical bias to the substrate support portion, or by supplying an electrical bias having a level of 200W or less or 1kV or less to the substrate support portion, wherein the plasma contains a hydrogen fluoride etchant.

[0086] According to the plasma treatment method described above [E1], the second film can be selectively removed relative to the first film.

[0087] [E2] According to the plasma processing method described in [E1], wherein, The aforementioned processing gas includes hydrogen fluoride gas.

[0088] [E3] According to the plasma processing method described in [E1] or [E2], wherein, The first membrane mentioned above is a carbon-containing membrane or a metal-containing membrane.

[0089] [E4] The plasma processing method according to any one of [E1] to [E3], wherein, The aforementioned base membrane is a metal-containing membrane.

[0090] In this case, since the base film is difficult to etch in (b), it is difficult to generate metal residue from the base film.

[0091] [E5] The plasma processing method according to any one of [E1] to [E3], wherein, The aforementioned base film is a silicon-containing film.

[0092] [E6] The plasma processing method according to any one of [E1] to [E5], wherein, The aforementioned processing gas further includes at least one selected from the group consisting of inert gases, fluorocarbon gases, hydrofluorocarbon gases, and phosphorus-containing gases.

[0093] [E7] The plasma processing method according to any one of [E1] to [E6], wherein, It further includes (c) the process of forming a deposit on the basement membrane exposed within the opening.

[0094] In this case, the base film is difficult to etch in (b).

[0095] [E8] According to the plasma processing method described in [E7], wherein, In (c) above, no electrical bias is supplied to the substrate support portion, and plasma is generated by a processing gas containing hydrogen halide gas and carbon-containing gas.

[0096] [E9] According to the plasma processing method described in [E8], wherein, The aforementioned hydrogen halide gas is hydrogen fluoride gas, hydrogen chloride gas, or hydrogen bromide gas.

[0097] [E10] According to the plasma processing method described in [E8] or [E9], wherein, The carbon-containing gases mentioned above are hydrocarbon gases, fluorocarbon gases, or hydrofluorocarbon gases.

[0098] [E11] The plasma processing method according to any one of [E1] to [E10], wherein, In (b) above, the temperature of the substrate support portion is 30°C or below.

[0099] [E12] The plasma processing method according to any one of [E1] to [E11], wherein, In (b) above, the pressure in the chamber is 6.67 Pa or more.

[0100] In this case, in (b), the etching selectivity of the second film relative to the first film can be improved.

[0101] [E13] A plasma processing method comprising: (a) A process of providing a substrate to a substrate support in a cavity, wherein the substrate has a base film, a first film on the base film and a second film on the first film, the second film having a first opening that exposes the first film, and the second film comprising silicon. (b) A process of etching the first film using a first plasma generated from the first processing gas to form a second opening in the first film; (c) A step of removing the second film using a second plasma generated from a second processing gas, wherein the second plasma contains a hydrogen fluoride etchant. In (c) above, no electrical bias is supplied to the substrate support portion, or in (b) above, an electrical bias of a level lower than that supplied to the substrate support portion is supplied to the substrate support portion.

[0102] [E14] The plasma processing method according to any one of [E1] to [E12], wherein, The above (b) includes: During a first period of supplying a first source RF signal for generating the aforementioned plasma, the first source RF signal has a first level; During the second period, which alternates with the first period described above, no source RF signal is supplied, or a second source RF signal with a second level lower than the first level described above is supplied.

[0103] [E15] A plasma processing method comprising: (a) A process of providing a substrate to a substrate support in a cavity, the substrate having a base film, a first film on the base film, and a second film on the first film, the first film and the second film having openings exposing the base film, the second film comprising silicon; and (b) A process of supplying an electrical bias to the substrate support portion and removing the second film using plasma generated by a processing gas, wherein the plasma contains a hydrogen fluoride etchant and the ionization energy generated by the plasma and injected into the substrate is 500 eV or less.

[0104] [E16] According to the plasma processing method described in [E15], wherein, The first membrane mentioned above is a carbon-containing membrane. The aforementioned base membrane is a metal-containing membrane.

[0105] [E17] According to the plasma processing method described in [E15] or [E16], wherein, Further including (c) the step of removing the first membrane in the chamber after (b) above.

[0106] [E18] The plasma processing method according to any one of [E1] to [E17], wherein, The spacing between the aforementioned openings is less than 80 nm.

[0107] [E19] A plasma processing apparatus, It is a plasma processing device, comprising: Chamber; The substrate support portion for supporting the substrate in the aforementioned cavity has a base film, a first film on the base film, and a second film on the first film. The first film and the second film provide openings that expose the base film. The second film contains silicon. A gas supply unit configured to supply processing gas into the aforementioned chamber; A plasma generating unit configured to generate plasma from the aforementioned processing gas within the aforementioned chamber, wherein the plasma contains a hydrogen fluoride etchant; and Control Department The control unit described above is configured to control the plasma processing apparatus in a manner that executes a plasma processing method, the plasma processing method comprising the following steps: (b) The second film is removed by plasma if an electrical bias is not supplied to the substrate support or an electrical bias of 200W or less or 1kV or less is supplied to the substrate support.

[0108] Explanation of symbols 1…Plasma processing apparatus, 2…Control unit, 10…Plasma processing chamber, 11…Substrate support unit, 12…Plasma generation unit, 20…Gas supply unit, F1…First membrane, F2…Second membrane, OP…Opening, OP1…First opening, OP2…Second opening, PL1…First plasma, PL2…Second plasma, UF…Base film, W…Substrate.

Claims

1. A plasma processing method comprising: (a) a step of providing a substrate onto a substrate support in a chamber, the substrate having a base film, a first film on the base film, and a second film on the first film, the first film and the second film providing openings to expose the base film, the second film comprising silicon; and (b) A process of removing the second film by means of plasma generated by a process gas, wherein the second film is removed by means of a plasma containing a hydrogen fluoride etchant, provided that the second film is not supplied with an electrical bias to the substrate support or is supplied with an electrical bias having a level of less than 200W or less than 1kV.

2. The plasma treatment method according to claim 1, wherein, The processing gas contains hydrogen fluoride gas.

3. The plasma treatment method according to claim 1 or 2, wherein, The first membrane is a carbon-containing membrane or a metal-containing membrane.

4. The plasma treatment method according to claim 1 or 2, wherein, The base membrane is a metal-containing membrane.

5. The plasma treatment method according to claim 1 or 2, wherein, The base film is a silicon-containing film.

6. The plasma treatment method according to claim 1 or 2, wherein, The processing gas further comprises at least one selected from the group consisting of inert gases, fluorocarbon gases, hydrofluorocarbon gases, and phosphorus-containing gases.

7. The plasma treatment method according to claim 1 or 2, wherein, The process further includes (c) the step of forming a deposit on the basement membrane exposed within the opening.

8. The plasma treatment method according to claim 7, wherein, In step (c), no electrical bias is supplied to the substrate support, and plasma is generated by a processing gas containing hydrogen halide gas and carbon-containing gas.

9. The plasma processing method according to claim 8, wherein, The hydrogen halide gas is hydrogen fluoride gas, hydrogen chloride gas, or hydrogen bromide gas.

10. The plasma processing method according to claim 8, wherein, The carbon-containing gas is a hydrocarbon gas, a fluorocarbon gas, or a hydrofluorocarbon gas.

11. The plasma processing method according to claim 1 or 2, wherein, In (b), the temperature of the substrate support portion is below 30°C.

12. The plasma processing method according to claim 1 or 2, wherein, In (b), the pressure inside the chamber is 6.67 Pa or higher.

13. A plasma processing method comprising: (a) a step of providing a substrate to a substrate support in a chamber, the substrate having a base film, a first film on the base film and a second film on the first film, the second film having a first opening exposing the first film, the second film comprising silicon; (b) The process of etching the first film using a first plasma generated from the first processing gas to form a second opening in the first film; (c) A step of removing the second film using a second plasma generated from a second process gas, the second plasma containing a hydrogen fluoride etchant. In (c), no electrical bias is supplied to the substrate support, or in (b), an electrical bias of a level lower than that supplied to the substrate support is supplied to the substrate support.

14. The plasma processing method according to claim 1, wherein, The (b) includes: During a first period of supplying a first source RF signal for generating the plasma, the first source RF signal having a first level; and During the second period, which alternates with the first period, no source RF signal is supplied, or a second source RF signal with a second level lower than the first level is supplied.

15. A plasma processing method comprising: (a) a step of providing a substrate onto a substrate support within a chamber, the substrate having a base film, a first film on the base film, and a second film on the first film, the first film and the second film providing openings to expose the base film, the second film comprising silicon; and (b) A process of supplying an electrical bias to the substrate support and removing the second film using plasma generated by a processing gas, the plasma containing a hydrogen fluoride etchant, the ionization energy generated by the plasma and injected into the substrate being less than 500 eV.

16. The plasma processing method according to claim 15, wherein, The first membrane is a carbon-containing membrane. The base membrane is a metal-containing membrane.

17. The plasma processing method according to claim 15, wherein, It further includes (c) the step of removing the first membrane in the chamber after (b).

18. The plasma processing method according to any one of claims 14 to 17, wherein, The spacing between the openings is less than 80 nm.

19. A plasma processing apparatus, comprising: chamber; A substrate support portion for supporting a substrate within the cavity, the substrate having a base film, a first film on the base film, and a second film on the first film, the first film and the second film providing openings to expose the base film, the second film comprising silicon; A gas supply unit configured to supply processing gas into the chamber; A plasma generation unit configured such that plasma is generated from the processing gas within the chamber, wherein the plasma contains a hydrogen fluoride etchant; and Control Department The control unit is configured to control the plasma processing apparatus in a manner that executes a plasma processing method, the plasma processing method comprising the following steps: (b) The second film is removed by plasma without supplying an electrical bias to the substrate support or by supplying an electrical bias at a level of 200W or less or 1kV or less to the substrate support.

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